One of the United States' most experienced diplomats says he's come away from behind-the-scenes conversations with Iranian officials this week thinking "it is possible to come to accommodations" with new President Hassan Rouhani and his aides on key issues such as Iran's nuclear ambitions.

"You make peace with your adversaries, not with your friends," Ryan Crocker tells Morning Edition host Steve Inskeep in a conversation broadcast Thursday. While Iran is an adversary, Crocker says, it seems possible now that its relations with the U.S. will improve.

Crocker, a former ambassador to Iraq and Afghanistan in Republican and Democratic administrations, is now dean at Texas A&M's George Bush School of Government & Public Service. He was among Americans invited to meet with Iranian officials this week at the United Nations.

What he heard, Crocker says, is that the new Iranian leadership is convinced that the U.S. and Iran "over the last half a dozen years have been playing into lose-lose scenarios, and both Iran and the United States are the worse for it. We need a new track."

Rouhani this week told Washington Post columnist David Ignatius that he wants to wrap up negotiations with the U.S. and other nations about Iran's nuclear program within the next three to six months. Crocker says that's what he was told by Iranian officials in his conversations, as well.

What Crocker says he also found interesting is that the Iranian leadership believes the negotiations should focus less on how many centrifuges Iran has and more on how much it's allowed to enrich uranium. In other words, the Iranians want to be able to have as many centrifuges as they think necessary and in exchange, says Crocker, the Iranians say they are willing to abide by "international norms" regarding enrichment of uranium. In theory, they would only enrich uranium to levels useful for peaceful purposes, not for weapons.

When President Obama and Rouhani were both in New York City on Tuesday, there was speculation they might cross paths. Crocker says he was told by Iranian officials that "both sides had agreed" that such a meeting would happen. But later, Iranians told him, both sides "decided it would be better to put it off" because there hadn't been time "for anything of substance to transpire."

Rouhani is also getting attention this week for saying on CNN that the Holocaust did indeed happen.